1. Technical Field
The present invention relates to a waterproof connector having a waterproof plug. The waterproof plug is used to seal a gap between a wire inserted into a terminal insertion hole of a connector housing and an inner wall surface of the terminal insertion hole formed in the connector housing.
2. Description of the Related Art
In an ordinary waterproof connector, when a terminal is inserted into a terminal insertion hole of a connector housing, a rubber waterproof plug is fitted to an outer circumferential surface of a wire extending from a terminal, and then the waterproof plug and the terminal are both pressure inserted into the terminal insertion hole together, so that a gap between the wire and the terminal insertion hole can be sealed. In the prior art waterproof plug, the rubber plug is formed into a cylindrical (circular in cross section) shape and formed with a central hole through which the wire can be passed. In addition, the rubber plug is formed with a front clamped portion clamped by the terminal and with a plurality of projections on the inner and outer circumferential surfaces of the cylindrical rubber for increasing the tightness against the wire and the terminal insertion hole, respectively. Further, the terminal insertion hole of tile connector housing is formed into a circular shape in the same way as the shape of the waterproof plug.
In the above-mentioned prior art waterproof plug, however, since the circular waterproof plug is inserted into the circular terminal insertion hole of the connector housing, when a plurality of terminals are arranged in a horizontal direction, a plurality of the circular terminal insertion holes are arranged also in the horizontal direction, so that there exists a problem in that the dimension of the connector housing increases in the horizontal (width) direction thereof and thereby the connector size becomes large.
To overcome this problem, Japanese Published Unexamined Utility Model Application 64-19271 discloses a connector housing formed with a plurality of oval terminal insertion holes arranged in the horizontal (width) direction thereof and a waterproof plug formed also into an oval shape. In more detail, in order to reduce the horizontal (width) dimension of the connector housing, each wire insertion hole is formed into an oval shape (including an ellipse, an elongated circle, a chamfered square, etc.) elongated in the vertical (height) direction, and a plurality of the oval wire Insertion holes are arranged in the horizontal (minor axis) direction. Further, the waterproof plug is also formed into roughly an oval shape according to the oval wire insertion holes.
In this prior art waterproof plug, however, whenever the oval waterproof plug is clamped to the terminal, the directions of both the terminal and the oval waterproof plug must be matched each other, and in addition the oval waterproof plug (to which tile terminal has been clamped) must be inserted into the oval terminal insertion hole after having been located in the correct direction relative to each other. In particular, when the directions of the oval waterproof plug and the terminal mismatch each other, the waterproof performance inevitably deteriorates. In addition, in order to mold the oval rubber waterproof plug, there exists another problem in that the molding dies are difficult to be manufactured and managed.
On the other hand, Japanese Published Unexamined Utility Model Application 61-23275 discloses a connector formed with a plurality of oval terminal insertion holes and a waterproof plug formed into a circular shape. In more detail, in order to reduce the horizontal (width) dimension of the connector housing, each wire insertion hole is formed into an oval shape elongated in the height direction, and a plurality of the oval wire insertion holes are arranged in both the horizontal (minor axis) and vertical (major axis) directions. In this prior art waterproof plug, therefore the circular waterproof plug is to be pressure inserted into the oval wire insertion holes of the connector housing to seal a gap therebetween.
In this prior art waterproof plug, since the waterproof plug is formed Into a circular shape, it is possible to overcome the problem involved in the oval waterproof plug. However, since the circular waterproof plug must be inserted into the oval wire insertion hole under pressurized and deformed condition, there exists such a problem that the wire insertion hole is easily deformed and thereby the gap between the wire and the wire insertion hole cannot be sealed perfectly, with the result that it is difficult to obtain a stable waterproof performance. In addition, since the waterproof plug must be deformed largely, a large force is inevitably required to deform the circular waterproof plug and further to insert the deformed waterproof plug into the oval wire insertion hole.